I currently own two tablets: the 10" Transformer Infinity and a Galaxy Tab (original one).

My Infinity is great and perfectly fine, but my Galaxy Tab though is getting a bit long in the tooth and starting to become obsolete due to software no longer being compatible, case in point, the latest versions of Mantano are not available for it.

I will state that I do love my tab, as it's been a great companion for quite a long time now, but there is a major issue with it. It was bought from Orange (due to being an Orange employee at that time and I got it on a great discount), so it's locked to Orange. Orange only upgraded the OS to Froyo (2.2) and declined the Gingerbread upgrade. This limits what new software I can install on it, so I've got a few options.

1. Root it and then somehow hack it to make it become a stock Galaxy Tab and then use Kies to install Gingerbread.
2. Root it and then install a different non-Samsung ROM.
3. Replace it with a new tablet.

Options 1 & 2 are possible, but I've never done this sort of thing before, so don't know how successful this will be, or even is the result will be worth the effort.

Option 3 is a possibility, but that one then presents me with a few more choices.

I'm in the UK so 4G is not that prevalent yet, I do live in Bristol and 4G is here. 3G though is readily available and I've got my 3G SIM from my Galaxy Tab so I could just stick it in.

Wifi isn't quite as available as I'd like, so might not be able to always get it, chances are, I'll probably have significant periods without connection to the net. The one advantage that a Wifi-only table will offer is that it's cheaper. So does the trade-off of no mobile network connection but cheaper outweigh having the mobile network connection but needing to pay a bit more for the tablet?

Lastly, if I look at getting an ebook tablet, what do I loose in comparison to a regular tablet? Or are they in fact better?

Lastly, if I look at getting an ebook tablet, what do I loose in comparison to a regular tablet? Or are they in fact better?

Beware tablets marketed as ebook readers. Like with the Kobo Vox, they are almost always underspecced, even compared to "proper" tablets of their own price range. The one exception to that, so far, is the new Kobo Arc - except for the lack of GPS, bluetooth, rear-facing camera, and microSD slot, it's better than most tablets in its price range (probably coming in second, out of the 7"-ers, to the Nexus 7 - N7's quad-core instead of dual-core, but hasn't got as good a screen as the Arc, but the N7 has a 3G version now, which could interest you).

I have the original Nexus 7 and it's a great device, but can't compare it to any other 7 incher. The speakers are incredibly loud for a tablet, if you ever want to watch movies or youtube on it, or listen to internet radio.
Like JD said, I would steer away from closed LCD readers like the Fire and Nooks, since they do not natively support the Google Play store, and have their own custom software on them.